Free throw administration

[Fritz]

Since we are on the topic of free throw administration, had this happen Mon night. 8th grade boys game. A1 at the line to shoot the first of two shots (foul on B1 while in the act of shooting, unsuccessful). After A1 releases the shot, B2 clearly steps into the lane before the shot reaches the vicinity of the basket. I say "vicinity" because the shot doesn't draw iron.

I'm lead and give the lane violation sign, then trail (2-man crew of course) blows the whistle on the no-rim. We consulted and my partner thought that because B1 violated first, we should re-shoot the shot. I thought that since it was a double violation, we wipe off that shot and just shoot the 2nd one.

Who is right? By the way, since my partner was the senior official, we went with his call and sold the coaches that way with no arguments.